BASICS OF MICROBIOLOGY
❖ Learning objects
❑ About introduction, history, scope & importance of microbiology.
❑ About introduction of Prokaryotes & Eukaryotes organisms.
❑ About detail study of Bacteria with respect to structure, their
classification, growth requirement, their isolation techniques &
qualitative measurements.
❑ About study of different types of microscopy for detection of
microorganisms.
A. INTRODUCTION
Microbiology is the branch of science which deals with microorganisms. They
also small living things that include unicellular, multicellular or acellular.
Unicellular – Single cell organisms like cocci, vibrio & spirillae.
Multicellular – Filaments & sheaths to form cell colonies like blue green algae
(cyanobacteria), fungi, protozoans & bacteria.
Acellular – without cell organisms like viruses, prions.
These microorganisms are not visible by naked eyes, only observed under
microscope.
Many microorganisms are beneficial to human & some are pathogenic in
nature.
B. HISTORY
The history of microbiology is divided into three stages namely Discovery
stage, Transition stage & Modern Microbiology.
01]. Discovery stages:
‘Aristotle’ described living & nonliving organisms & their differentiation.
‘Roger bacon’ described disease are caused by living creatures.
‘Fracastorius’ described communicable disease were caused by living agents
known as germs.
‘Robert Hook’ described first report on cell structure.
‘Antony van Leeuwenhoek’ first person who used a microscope of his own
design to direct observation of microbes. Form the time he was known as one
of the founders of microbiology.
02]. Transition stage:
‘Francesco Redi’ maggots would not arise form decaying covered meat.
‘John Needham’ proposed that tiny organisms arise spontaneously on the
mutton gravy & he support the spontaneous generation theory.
‘Lazzaro Spallanzani’ air carried germs to culture medium & also revealed that
boiled broth would not give growth of microorganisms.
‘John Tyndall’ proved the need for prolonged heating for elimination of
microbial life from infusions.
‘Augustino Bassi’ silk worm disease called muscardine was due to fungal
infection.
03]. Modern Microbiology:
‘Louis Pasteur’ is also known as father of microbiology, because he was coined
the terms microbiology, aerobic & anerobic.
‘Lord Joseph lister’ is known as father of antiseptic surgery.
‘Robert Koch’ he gave first germs theory of diseases.
‘Paul Erlich’ discovered the treatment of syphilis by using arsenic
(arsphenamine).
‘Alexander Flaming’ who discovered world’s first antibiotic substance
benzylpenicillin form the mould penicillium notatum.
C. BRANCHES OF MICROBIOLOGY
Microbiology is classified into main three branches which are tabulated below:
MICROBIOLOGY
By taxonomy By type of research Applied microbiology
By Taxonomy By types of research Applied microbiology
Bacteriology Astromicrobiology Medical microbiology
Immunology Evolutionary microbiology Pharmaceutical microbiology
Mycology Microbial physiology Industrial microbiology
Nematology Microbial ecology Microbial biotechnology
Parasitology Microbial genetics Agricultural microbiology
Phycology Cellular microbiology Veterinary microbiology
Protozoology Nano microbiology Environmental microbiology
Virology Molecular microbiology geomicrobiology
Biological agent Aero microbiology
Generation microbiology Aquatic microbiology
D. SCOPE OF MICROBIOLOGY
Some of the recent scopes are highlighted below:
01. Ecology & environment applications.
02. Food microbiology.
03. Medicines: clinical & pharmaceutical microbiology.
04. Disease treatment.
05. Vaccine & immunology.
06. In Genetic engineering.
07. In Biochemistry & physiology.
08. In Industries.
09. In Agricultural field.
10. Geochemical applications.
11. Exomicrobiology
E. IMPORTANCE OF MICROBIOLOGY
The importance of microbiology in various fields is such as;
Pharmaceutical industry.
Medical devices.
Cosmetic microbiology.
Microbiology processes are used in waste treatment, particularly dumping, waste
incineration, composting & biomethanization.
MORPHOLOGICAL CLASSIFICATION OF BACTERIA
As per morphological basis, bacteria are classified into six major groups as follows:
MORPHOLOGY OF BACTERIA
True Actinomycetes Spirochaetes Mycoplasmas Chlamydiae Rickettsiae
bacteria
Cocci Bacilli
01.True bacteria – They further divided in to two sub-groups namely Cocci &
Bacilli.
Cocci are various type: like
⚫ Mono cocci = Monococcus Species.
⚫⚫ Diplococci = Streptococcus Pneumonia.
⚫⚫ Tetrad = Micrococcus Species.
⚫⚫
Sarcina = Sarcina Ventriculi.
⚫⚫⚫⚫⚫⚫⚫ Streptococci = Streptococcus Pyogenes.
⚫⚫⚫ Staphylococci = Staphylococcus Aureus.
⚫⚫
⚫
Bacilli are various type: like
Coccobacilli Bacillus Diplobacilli
Streptobacilli
Palisades
Club rod Enlarged rod
02. Actinomycetes: It looks like fungi. They are widely distributed in soil,
compost etc. they are heterotrophic, aerobic & mesophilic organisms.
01.
02. 03
03. Spirochaetes: They are double membrane bacteria, most have long, non-
branched, helically coiled cells.
The length varies between 3 to 500m & diameter around 0.09 to 3m.
Ex. Leptospira interrogans.
Spirochaetes
04. Mycoplasmas: They are small bacteria cell & not having rigid cell wall. They
are highly pleomorphic in nature. They can parasitic or saprotrophic.
Ex. Mycoplasma Pneumoniae.
Ribosome
Cell Membrane
DNA
05. Rickettsia: They are no-motile, gram negative, non-spore forming,
small intracellular & pleomorphic bacteria.
They are also present as cocci, rods or thread-like forms.
Ex. Rickettsia conorii, Rickettsia typhi etc.
06. Chlamydiae: They are ovoid in shape & gram-negative bacteria.
They are very small, obligate intracellular parasites.
Ex. Chlamydia trachomatis & Chlamydophila pneumonia.
